A 40-year-old Murdock, Nebraska, man was found dead in a jail cell Saturday night, the Cass County Sheriff’s Office said.

Jail staff found Dustyn R. Gandara unresponsive 12 minutes after they had last checked on him, Sheriff William Brueggemann said in a statement.

Gandara had been sentenced to 30 days in jail Friday after pleading guilty to driving under the influence of alcohol or drugs.

An autopsy was performed Sunday. The results are pending, Brueggemann said.

Investigators from the Nebraska State Patrol, Plattsmouth Police Department and the Sheriff’s Office were looking into Gandara’s death. State law requires a grand jury investigation of any in-custody death.